How To Test The MAP Sensor (1996-2000 3.3L V6 Caravan, Grand Caravan, Voyager, Grand Voyager, Town & Country)

  • By: Abraham Torres-Arredondo
  • Created: 14 April 2025
  • Updated: 14 April 2025
  • Articl Id: 1609
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TEST 3: Making Sure The MAP Sensor Is Getting Ground

Making Sure The MAP Sensor Is Getting Ground. How To Test The MAP Sensor (1996, 1997, 1998, 1999, 2000 3.3L V6 Caravan, Grand Caravan, Voyager, Grand Voyager)

By now, your MAP sensor diagnostic has nailed down two key facts:

  • First: The MAP sensor isn't responding to vacuum —it's not showing a voltage drop or rise when vacuum is applied or released.
  • Second: The sensor is getting a solid 5 Volts of power straight from the PCM.

To wrap things up and confirm the sensor's really done for, there's one last check: make sure it's getting Ground. Without a good Ground connection, it simply won't work.

IMPORTANT: This Ground wire runs directly to the PCM (it supplies Ground internally). So whatever you do —don't feed battery power (12 Volts) into this wire, or you risk frying the PCM. The test below is a safe way to test for Ground in the wire.

Here's how to check for Ground safely:

  1. 1

    Disconnect the MAP sensor from the harness connector.

  2. 2

    Connect your multimeter's red lead to the battery's positive (+) terminal.

  3. 3

    Set the multimeter to Volts DC mode.

  4. 4

    Turn the ignition to the ON position, but don't crank the engine.

  5. 5

    Use the black lead to probe the front of terminal number 1 on the connector (refer to the photo above if needed).

  6. 6

    You should see a voltage reading between 10 and 12 Volts.

Here's what those results mean:

CASE 1: You saw 10 to 12 Volts on your multimeter. That's exactly what you want. It proves the PCM is providing a clean Ground connection.

At this point, if you've already:

  • Confirmed the MAP sensor isn't reacting to vacuum changes (TEST 1),
  • Verified it's getting a solid 5 Volt power feed (TEST 2),
  • And now confirmed it has Ground (this test),

…then you've got your answer: the MAP sensor is bad and needs to be replaced.

CASE 2: You didn't get 10 to 12 Volts on the meter. Double-check your setup and make sure your connections are solid.

If it's still not showing that voltage, the MAP sensor isn't the issue —it can't operate without a working Ground circuit.

Tracking down the reason behind the missing Ground is outside the scope of this guide, but at least now you know the MAP sensor itself isn't to blame.

Once you restore that missing Ground path, your MAP sensor problems on the 3.3L V6 mini-van should be gone.

MAP Sensor Code Won't Go Away

There are a bunch of problems that can fool the PCM in your 3.3L V6 mini-van into thinking the MAP sensor's bad —even when it's perfectly fine.

If you've already tested or swapped out the MAP sensor, but that check engine light keeps coming back (even after you've cleared the code and taken the van for a spin), check out these other possible causes that could be triggering the code:

  • Big vacuum leak: A torn intake manifold gasket or cracked, dry-rotted vacuum hoses can throw off engine vacuum. That messes with the MAP sensor's readings and confuses the PCM.
  • Poor compression across multiple cylinders: Low compression causes a rough idle and weak, inconsistent vacuum. That's enough to make the PCM think the MAP sensor's acting up.
  • MAP sensor cutting out now and then: Sometimes the sensor works most of the time, but randomly stops responding. That's what we call an intermittent failure.
    • Try this: while applying vacuum, give the sensor a light tap with the handle of a screwdriver. If the voltage signal jumps or glitches, it's failing internally.
  • Loose or damaged connector: If the connector locking tab's broken, it might not stay fully seated. That can cause the sensor to lose contact now and then.
  • Weak fuel pump: A fuel pump that's not sending the proper amount of fuel to the injectors can affect engine performance and trick the PCM into misreading sensor data. A fuel pressure test will help sort this out.
  • EGR valve stuck open: If your engine has an EGR valve and it's jammed open, it'll cause performance issues and mess with vacuum levels —which can confuse the MAP sensor readings.

More 3.3L Chrysler, Dodge, And Plymouth Mini-Van Tutorials

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